The prior art suggests that ribosomal proteins might play an important role in certain diseases, disorders or conditions. More specifically, there are many reports demonstrating a connection between over expression of the mRNA of genes encoding ribosomal proteins and cancer (Chiao et al., 1992, Mol. Carcinog. 5:219-231; Femandez-Pol et al., 1993, J. Biol. Chem. 268:21198-211204; Femandez-Pol et al., 1994, Cell Growth & Differentiation 5:821-825; Fernandez-Pol, 1996, Anticancer Res. 16:2177-2186; Chan et al., 1996, Biochem. and Biophys. Res. Comm. 228:141-147; Chan et al., 1996, Biochem. and Biophys. Res. Comm. 225:952-956; Wool, 1996, Trends in Biochemical Sciences 21:164-165; Wool et al., 1995, Biochem. Cell Biol. 73:933-947; and Vaarala et al., 1998, Int. J. Cancer 78:27-32). For instance, Chiao et al. (1992, Mol. Carcinog. 5:219-231) determined that expression of the S2-ribosomal protein mRNA was elevated in head and neck cancer, but the S2 mRNA was barely detectable in normal tissue. Based upon these studies, it is believed that the over expression of several ribosomal mRNA's might thereby be associated with the development of cancer. For example, it has been proposed that specific zinc finger, leucine zipper motifs, bZIP elements, helix-turn-helix motifs or other motifs characteristic of several ribosomal proteins (e.g., e. coli L7, rat S27 and S29) may bind to nucleic acids (Chan et al. Nucleic Acids Res. 1993; 21:649-655; Femandez-Pol et al., 1996, Anticancer Res. 16:2177-2186; Wool, 1996, Trends in Biochemical Sciences 21:164-165; Wool, 1997, In: The ribosomal RNA and Group I introns, pp. 153-178, Green and Schroeder, eds., R. G. Landes Co., Austin, Tex.). Others have found that the rat ribosomal protein S3a is identical to the rat v-fos transformation effector protein (Chan et al., 1996, Biochem. Biophys. Res. Comm. 228:141-147). S3a is normally involved in initiation of protein synthesis and is also related to proteins involved in the regulation of growth and the cell cycle (Chan et al., 1996, Biochem. and Biophys. Res. Comm. 228:141-147). Likewise, the rat ribosomal protein L10 is homologous to a putative Wilm's tumor suppressor gene (Chan et al., 1996, Biochem. Biophys. Res. Comm. 225:952-956). Malignant cells may express mutant ‘ribosomal-like’ proteins. However, there is currently no evidence that any of these ribosomal proteins are over expressed or that the proteins acquire DNA binding activities in malignant cells.
The existence of chromosomal abnormalities in lymphoid tumors is well established. Chromosomal translocations associated with T cell acute lymphoblastic leukemia (T-ALL) have led to the identification of several potential oncogenes (Rabbitts, 1991, Cell 67:641-644). Many of the T-ALL associated chromosomal translocations have been localized to the T-cell receptor (TCR) genes. Recombination of the immunoglobulin gene takes place at early phase of B-lymphocyte differentiation. The V-(D)-J recombination that joins two or three germline segments (i.e., variable-V; diversity-D; and joining-J) segments into a variable-gene exon by site-specific recombination contributes to amplification of the V-region diversity. Comparison of the nucleotide sequences of the flanking regions of the V, D, and J segments has demonstrated that two common blocks of nucleotide sequences are conserved (Early et al., 1980, Cell 19:981-992), including a heptamer CACTGTG and a T-rich nonamer GGTTTTTGT, which are separated by a spacer sequence of either 12 or 23 bases. The homology between the heptamer-spacer-heptamer-nonamer sequences of the T-cell receptor and immunoglobulin genes suggests that these elements, commonly referred to as Break Point Cluster Regions or BPCRs, play an important role in V-(D)-J recombination.
The prior art suggests that DNA binding protein(s) that recognize the conserved recombination signal sequence (RS) may be involved in the recombinational machinery that cleaves DNA at the juncture between the signal and coding region sequences and ligates the cleaved ends. Earliest reports disclosed RS proteins as being located in lymphoid cells (Aguilera et al., 1987, Cell 51:909-917; Halligan and Desiderio, 1987, Proc. Natl. Acad. Sci. USA 84:7019-7023; Hamaguchi et al., 1989, Nucleic Acid Res. 17:9015-9026; and Mak, 1994, Nucleic Acid Res. 22:383-390). More recently, different RS proteins have been identified. For example, a DNA binding protein for kappaB binding and recognition component of the V(D)J recombination signal sequence has been identified. Activation of this family of transcription factors is thought to provide a mechanism by which oncogenic tyrosine kinases regulate genes with kappaB-controlled gene regulatory elements.
Studies on T cell abnormalities have been particularly informative with respect to recombinase involvement, especially with respect to breakpoints within the chromosome band 11p13. It seems that recombinase is responsible for abnormal chromosomal unions, because often both reciprocal translocated chromosomes have N-region nucleotide addition, which is a hallmark of recombinase activity (Alt and Baltimore, 1982, Proc. Natl. Acad. Sci. USA 79:4118-4123). These translocations are regarded as mutations of the normal chromosomal joining process.
In sum, the mechanism(s) by which chromosomal abnormalities associated with rearranging genes come about and the role of DNA binding enzymes involved in the normal antigen receptor gene rearrangement (i.e., recombinases) (Croce, 1987, Cell 49:155-169), albeit well-studied, are still poorly understood. Thus, identification of new BPCRs and new recombinases is needed, especially for understanding non-lymphoid type diseases and solid cancer development.
Further, although prior studies suggest that DNA binding proteins are associated with and/or mediate certain diseases, disorders or conditions, very few of these proteins have been identified (e.g., to date, none have been identified in solid cancers) and their role(s) in the disease process is poorly understood. This is so despite the fact that there are various prior art assays for identification of DNA binding proteins (e.g., Weissman et al., 2000, U.S. Pat. No. 6,066,452; Edwards et al., 2000, U.S. Pat. No. 6,010,849; Edwards et al., 1999, U.S. Pat. No. 5,869,241; Sukhatme, 1999, U.S. Pat. No. 5,866,325). Thus, there is a long-felt need for a simple, effective assay for the identification of DNA binding proteins and their cognate duplex DNA sequence binding sites.
In addition, despite the potential usefulness of DNA binding proteins in the diagnosis and the development of therapeutics, there are few, if any, diagnostics and therapeutics based on DNA binding proteins or their cognate binding DNA duplexes.
Although prostate cancer is one of the leading causes of cancer-related mortality and morbidity in men, there are few effective diagnostics and therapeutics for this disease, and none are based on detection of a DNA binding protein, including proteins, which bind BPCRs. To date, there have been approximately 450 partially characterized tissue markers identified in the scientific literature, but only one has been developed as a clinical marker approved by the FDA, i.e., prostate specific antigen (PSA) and it's derivatives. Despite the dearth of useful markers for diagnosis and detection of cancers, including, but not limited to, prostate cancer, development of markers for the early detection of cancers is essential to improved treatment of cancer.
With respect to prostate cancer, it is generally believed that serum prostate specific antigen (PSA) levels are neither sensitive nor specific for identification of patients with prostate cancer (Gamick and Fair, 1998, Scientific Amer. December:75-83). It has been estimated that as many as 40% of men with prostate cancer have normal PSA levels (i.e. false negatives) and conversely, 30% of men with elevated PSA levels do not have PCA. Thus, development of more sensitive and specific assays for cancer, including prostate cancer, is imperative. Further, non-invasive and inexpensive urine-based screening assays, which would enable widespread implementation through mass community screening programs or in routine clinical examinations, would be particularly useful in diagnosis and treatment of cancers, including prostate cancer.
In sum, there is a long felt and acute need for identification and characterization of DNA binding proteins and the cognate duplex DNA molecules they specifically bind, especially for the development of diagnostics and therapeutics for diseases, disorders or conditions associated with altered expression of a DNA binding protein. Further, there is a long-felt and acute need for improved diagnostics and therapeutics related to cancer, including prostate cancer. The present invention meets these needs.